A known device of this type (German Published Patent Application No. 198 26 047) has, as an actuator or valve positioner, a double-acting hydraulic working cylinder in which a control piston is guided so as to be axially displaceable, this control piston being fixedly connected with the valve shaft of the gas exchange valve integrated in the combustion cylinder, or itself forming the end thereof further away from the valve closing element. In the working cylinder, the control piston limits, with its two end surfaces facing away from one another, an upper and lower working chamber. While the lower working chamber, via which a piston displacement in the direction of valve closing is effected, is constantly charged with a medium under high pressure, for example hydraulic oil, the upper working chamber, via which a piston displacement in the direction of valve opening is effected, is purposively charged with pressure medium that is under high pressure, or is again relieved of stress to approximately ambient pressure, with the aid of electric control valves, preferably 2/2-way magnetic valves. The pressure medium under high pressure is supplied by a high-pressure pump. Of the control valves, a first control valve connects the first working chamber with the high-pressure pump, and a second control valve connects the upper working chamber with a relief line that debouches into a pressure medium reservoir. In the closed state of the gas exchange valve, the upper working chamber is separated from the closed first control valve by the high-pressure pump, and is connected with the relief line via the opened second control valve, so that the control piston is guided into its closed position by the pressure of the medium prevailing in the lower working chamber. For the opening of the gas exchange valve, the control valves are switched over, through which the upper working chamber is closed off from the relief line and is connected to the high-pressure pump. Because the piston area of the control piston in the upper working chamber is larger than the effective surface of the control piston in the lower working chamber, the control piston is displaced so as to open the gas exchange valve. The magnitude of the opening stroke depends on the design of the electrical control signal applied to the first control valve, and the speed of opening depends on the high pressure of the pressure medium, applied by the high-pressure pump.
From German Published Patent Application No. 30 14 028, a fuel injection pump for internal combustion engines is known that has a pumping and distribution plunger that simultaneously executes a back-and-forth stroke motion and a rotational motion. The pumping and distribution plunger, formed as a stepped piston, limits a pump chamber. In the jacket surface of the pumping and distribution plunger, there is situated a distribution longitudinal groove that is connected with the pump chamber and that, during rotation, successively activates pressure passages that lead to pressure lines that are connected with the internal combustion engine. The number of pressure passages corresponds to the number of combustion cylinders in the internal combustion engine that are to be supplied. During the rotation of the pumping and distribution plunger, the pressure passages that are not under high pressure are successively relieved of pressure, to a suction chamber, via one or more longitudinal grooves, an annular groove, and a relief bore. The regulation of the injected fuel quantity takes place via a spool valve that is situated on the pumping and distribution plunger in axially displaceable fashion and can be axially displaced by an hydraulic controller. The pumping chamber is connected, via bored holes in the pumping and distribution plunger, with longitudinal grooves situated on the jacket surface thereof that work together with an opening in the spool valve. As long as these bored holes are controlled to open by the molded opening via the longitudinal grooves, no injection takes place. However, as soon as these bored openings are blocked, and simultaneously, during the pressure stroke of the pumping and distribution plunger, the distribution longitudinal groove coincides with one of the pressure passages, injection takes place. The injected quantity is thus determined by the spacing of the longitudinal grooves, at least one of the longitudinal grooves being situated obliquely to the other, so that an axial displacement of the spool valve causes an alteration of the activation distance, and thus of the injected quantity.
Through further rotation of the spool valve, the beginning and end of the injection are simultaneously displaced.
What is known as a control-sleeve in-line fuel-injection pump is known for diesel engines (Bosch, “Automotive Handbook”, 23rd ed., ISBN 3-528-03876-4, pp. 542 and 543), having, for each combustion cylinder of the diesel engine, a pump plunger that limits a pump chamber and is driven by a cam and that has an oblique control groove that is connected with the pump working chamber, and what is known as a control sleeve that is provided with a spill port. A setting shaft having a plurality of control-sleeve levers, of which each engages in a respective control sleeve, moves all the control sleeves in common. An electromagnetic actuator mechanism in turn rotates the setting shaft. According to the position of the control sleeve, the delivery begins earlier or later relative to the actuating cam. The delivery end is achieved when the control groove and the spill port coincide.